Patterns and Characteristics of Ambulance Attendance at Heroin Overdose at a Local-Area Level in Melbourne, Australia: Implications for Service Provision

The monitoring of heroin use and related harms is undertaken in Australia with a view to inform policy responses. Some surveillance data on heroin-related harms is well suited to inform the planning and delivery of heroin-related services, such as needle and syringe provision. This article examines local-area variation in the characteristics of nonfatal heroin overdoses attended by ambulances in Melbourne over the period June 1998 to October 2000 to inform the delivery of services to the heroin-using population in Melbourne.

An observer design procedure for a class of nonlinear time-delay systems

This paper considers a class of uncertain, nonlinear differential state delayed control systems and presents a reduced-order observer design procedure to asymptotically estimate any vector state functionals. The method proposed involves decomposition of the delayed portion of the system into two parts: a matched and mismatched part. Provided that the rank of the mismatched part is less than the number of the outputs, a reduced-order linear functional observer, with any prescribed stability margin, can be constructed by using a simple procedure. A numerical example is given to illustrate the new design procedure and its features.

Spatial, temporal and size-class variation in the diet of estuary perch (Macquaria colonorum) in the Hopkins River, Victoria, Australia

The dietary importance of prey of estuary perch (Macquaria colonorum; Percicthyidae: Günther) was examined spatially, temporally and among size classes. Fish were collected from the Hopkins River, south-western Victoria, from September 1998 to February 1999. The species is a euryhaline, euryphagic carnivore with spatial, temporal and size class variations in diets. Fish caught from estuarine locations consumed primarily Paratya australiensis (40% IRI) while freshwater fish consumed mostly Tricopteran larvae (63.5% IRI). In both freshwater and estuarine locations, the relative importance of P. australiensis decreased with increasing length of fish. Diet changed seasonally, indicating opportunistic changes in prey. The species selected particular prey items relative to environmental availability (P. australiensis, Amarinus lacustrine).

Class library ranlip for multivariate nonuniform random variate generation

This paper describes generation of nonuniform random variates from Lipschitz-continuous densities using acceptance/rejection, and the class library _ranlip which implements this method. It is assumed that the required distribution has Lipschitz-continuous density, which is either given analytically or as a black box. The algorithm builds a piecewise constant upper approximation to the density (the hat function), using a large number of its values and subdivision of the domain into hyperrectangles. The class library _ranlip provides very competitive preprocessing and generation times, and yields small rejection constant, which is a measure of efficiency of the generation step. It exhibits good performance for up to five variables, and provides the user with a black box nonuniform random variate generator for a large class of distributions, in particular, multimodal distributions. It will be valuable for researchers who frequently face the task of sampling from unusual distributions, for which specialized random variate generators are not available.

Training for the new work order : the adult classroom as a site of class(ed) work

This paper reports on a qualitative case study that investigated how the professional identities of trainers in the adult sector in Australia are shaped by intersecting relations of social class, ethnicity, gender and the discourses of vocational adult education. Interviews with two trainers as well as observations of them at work are analysed and presented here to illustrate how social class, considered in relation to gender and race, is played out through the trainers' identity investments in discourses of nurturance and care and economic rationalism. Such identity investments shape the relationships the trainers develop with their students and the training strategies and practices they privilege. The paper argues the need for trainers to develop critical reflective practices and to interrogate how their investments in particular classed identities shape their views about learning for work and training for work. It also argues the need for more research around social class and trainer identity within the adult sector.

Perceptions of the host destination as a result of attendance at a special event: a post-consumption analysis

Many destinations are now using special events as integral components of their marketing strategies. The aim of this study was to explore how  attendance at a special event might impact perceptions of the host destination. Using a case study approach, this research explored the nexus between special events, their attendees and special event destinations. This research specifically focused on exploring whether attendance at a special event influences resulting perceptions of the host destination. The results of a survey-based study indicate that for almost a quarter of respondents who resided outside the host destination, their perceptions of the host destination had changed. Over 90% of these respondents indicated that these post-consumption perceptions of the host destination were more favourable than they were before attendance at the event. Key reasons provided by respondents for their changes in perceptions included Access, the Special Event itself and Attractions at the destination. The paper concludes that the synergies between the special event and the host destination can be likened to those of the celebrity and the products that they endorse and promote, and this notion should be further explored. Recommendations were made to assist marketers of host destinations to more effectively capitalise on the synergies between special events and destinations.

Troubling identities: teacher education students` constructions of class and ethnicity

Working with diverse student populations productively depends on teachers and teacher educators recognizing and valuing difference. Too often, in teacher education programs, when markers of identity such as gender, ethnicity, 'race', or social class are examined, the focus is on developing student teachers' understandings of how these discourses shape learner identities and rarely on how these also shape teachers' identities. This article reports on a research project that explored how student teachers understand ethnicity and socio-economic status. In a preliminary stage of the research, we asked eight Year 3 teacher education students who had attended mainly Anglo-Australian, middle class schools as students and as student teachers, to explore their own ethnic and classed identities. The complexities of identity are foregrounded in both the assumptions we made in selecting particular students for the project and in the ways they constructed their own identities around ethnicity and social class. In this article we draw on these findings to interrogate how categories of identity are fluid, shifting and ongoing processes of negotiation, troubling and complex. We also consider the implications for teacher education.

An empirical analysis of gender differences in sports attendance motives

In Australia, male sports attendees outnumber female sports attendees by 25%, yet little research has been conducted into the attendance motives of women. This study undertakes an analysis of 460 respondents using descriptive and multivariate statistics to distinguish the attendance motivations of women and compare them directly to those of male attendees. The findings suggest that female attendance can be influenced through management and promotional strategies.

Integrating local one-class classifiers for image retrieval

In content-based image retrieval, learning from users’ feedback can be considered as an one-class classification problem. However, the OCIB method proposed in [1] suffers from the problem that it is only a one-mode method which cannot deal with multiple interest regions. In addition, it requires a pre-specified radius which is usually unavailable in real world applications. This paper overcomes these two problems by introducing ensemble learning into the OCIB method: by Bagging, we can construct a group of one-class classifiers which emphasize various parts of the data set; this is followed by a rank aggregating with which results from different parameter settings are incorporated into a single final ranking list. The experimental results show that the proposed I-OCIB method outperforms the OCIB for image retrieval applications.

Parameter optimization of kernel-based one-class classifier on imbalance learning

Compared with conventional two-class learning schemes, one-class classification simply uses a single class in the classifier training phase. Applying one-class classification to learn from unbalanced data set is regarded as the recognition based learning and has shown to have the potential of achieving better performance. Similar to twoclass learning, parameter selection is a significant issue, especially when the classifier is sensitive to the parameters. For one-class learning scheme with the kernel function, such as one-class Support Vector Machine and Support Vector Data Description, besides the parameters involved in the kernel, there is another one-class specific parameter: the rejection rate v. In this paper, we proposed a general framework to involve the majority class in solving the parameter selection problem. In this framework, we first use the minority target class for training in the one-class classification stage; then we use both minority and majority class for estimating the generalization performance of the constructed classifier. This generalization performance is set as the optimization criteria. We employed the Grid search and Experiment Design search to attain various parameter settings. Experiments on UCI and Reuters text data show that the parameter optimized one-class classifiers outperform all the standard one-class learning schemes we examined.

Parameter estimation of one-class SVM on imbalance text classification

Compared with conventional two-class learning schemes, one-class classification simply uses a single class for training purposes. Applying one-class classification to the minorities in an imbalanced data has been shown to achieve better performance than the two-class one. In this paper, in order to make the best use of all the available information during the learning procedure, we propose a general framework which first uses the minority class for training in the one-class classification stage; and then uses both minority and majority class for estimating the generalization performance of the constructed classifier. Based upon this generalization performance measurement, parameter search algorithm selects the best parameter settings for this classifier. Experiments on UCI and Reuters text data show that one-class SVM embedded in this framework achieves much better performance than the standard one-class SVM alone and other learning schemes, such as one-class Naive Bayes, one-class nearest neighbour and neural network.

Ian's story : the complex interaction of ethnicity, class and masculinities

In this paper, a narrative is used to convey the complex connectedness that exists between class, ethnicity and masculinity. The story is of Ian, a successful academic who describes himself as Eurasian, and traces his development through parts of his childhood and into his professional career, using what Gough (1994) describes as a 'realistic fiction'. Relevant literature on masculinities and ethnicity is considered. There is some evidence to suggest that Ian has developed a fluid version of masculinity as a result of his Asian-Australian upbringing, and that he expresses different masculinities according to the social settings in which he finds himself. The paper concludes, just as Ian's story does, that masculinity interacts with class and ethnicity. This accords with Connell's (1995) caution that it is dangerous to think that there is a colored masculinity or a working class masculinity, and that the milieux of class and race need to be considered as well.